// until any memory allocated from it is no longer needed.
//
// An Arena must never be used concurrently by multiple goroutines.
type Arena struct {
	a unsafe.Pointer
}

// NewArena allocates a new arena.
func NewArena() *Arena {
	return &Arena{a: runtime_arena_newArena()}
}

// Free frees the arena (and all objects allocated from the arena) so that

#include <stdio.h>
#include <stdlib.h>

/* Test calling panic from C.  This is what SWIG does.  */

extern void crosscall2(void (*fn)(void *, int), void *, int);
extern void _cgo_panic(void *, int);
extern void _cgo_allocate(void *, int);

void
callPanic(void)
{
	struct { const char *p; } a;
	a.p = "panic from C";
	crosscall2(_cgo_panic, &a, sizeof a);
	*(int*)1 = 1;

//go:build gccgo

#include "_cgo_export.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

/* Test calling panic from C.  This is what SWIG does.  */

extern void _cgo_panic(const char *);
extern void *_cgo_allocate(size_t);

void
callPanic(void)
{
	_cgo_panic("panic from C");

func test21897(t *testing.T) {
	// Please write barrier, kick in soon.
	defer debug.SetGCPercent(debug.SetGCPercent(1))

	for i := 0; i < 10000; i++ {
		testCFNumberRef()
		testCFDateRef()
		testCFBooleanRef()
		// Allocate some memory, so eventually the write barrier is enabled
		// and it will see writes of bad pointers in the test* functions below.
		byteSliceSink = make([]byte, 1024)
	}
}

var byteSliceSink []byte

holding the C pointers and use runtime.SetFinalizer on those Go objects.

It is much more difficult for the C world to have pointers into the Go
world, because the Go garbage collector is unaware of the memory
allocated by C.  The most important consideration is not to
constrain future implementations, so the rule is that Go code can
hand a Go pointer to C code but must separately arrange for